The Prime Minister's Office directed Canadian immigration officials to stop processing a preliminary group of Syrian refugees in the spring pending an audit of their cases.

Conservative Leader Stephen Harper has acknowledged that his government asked for an audit of Syrian refugee cases earlier this year, but denies that any political staff were involved in vetting those files.

Harper, responding to a Globe and Mail story, said that when it comes to admitting refugees, his government ensures the selection of the most vulnerable people while keeping the country safe and secure.

"The audit we asked for earlier this year was to ensure that these policy objectives are being met. Political staff are never involved in approving refugee applications," Harper said. "Such decisions are made by officials in the Department of Citizenship and Immigration."

Earlier, Citizenship and Immigration Minister Chris Alexander confirmed a news report Wednesday that the Prime Minister's Office directed Canadian immigration officials to stop processing a preliminary group of Syrian refugees, pending an audit of their cases.